Watch out here; JD parts prices are obscene. Ex. $480 for the 400 series radiator!! $275 for the seat structure (not seat, just the handfull of steel bars bolted to a couple plates). Drove me to do a little research and in general feel JD is way out of line on parts--they must view it as a core profit center. They want $150 for a 1 gallon gas tank for my old JD110--nothing special, just a tin can of the proper dimensions. Have a JD455 and mostly unimpressive. Feel you much more utility out of a compact tractor--learned the hard way going through the product line of L&G's (Sears, JD, Honda).
Would guess $5-6000 is going price on the unit. Varies by region and demand. Check local JD dealers for used and knock off 20% (for some reason folks think a dealer bought used is worth more). Check out the Kubota BX ($10K+ new), but 4x4 and loader that actually works. No comparison to the JD 400 series.